It’s been a long time since I last work on any hobby project and update on my blog. Recently, I completed a mini project together with two of my friends. So I am going to take this opportunity to share the project that we have made, we named it the Bridge Monitoring System (BMS) using Wireless Sensor Network (WSN). We are required to design an embedded system that is related with disaster management, either mitigation, preparedness, response or rehabilitation. To give you a high level overview of this project, basically we created three sensor nodes that acquire sensor measurement and transmit to central hub through wireless network. The sensor network works in a many-to-one fashion and data processing is done on the central hub. All the sensor measurement from each node is also displayed on the Host PC for user interface. Therefore, in this article, I am going to walk through some details of the project and how it works.
The figure above shows the high level block diagram of this system. There are three sensor nodes which are controlled by an Arduino Nano. Each sensor node are equipped with various sensors and they are exactly the same as other sensor node. All these sensor nodes will communicate with the central hub using the nRF24L01 wireless module. Sitting at the central hub is the CT-ARM, this is where all the sensor measurement are sent and processed. All the measurement obtained are also sent to a Host PC for display through UART communication. On the Host PC, LabVIEW is used to create a nice user interface to view all the sensor measurements.
Let us look into more details for the central hub. As mentioned previously, the central hub is comprised of the Cytron ARM Cortex M0 (CT-ARM). CT-ARM is an Arduino compatible which uses the 32-bit Nuvoton NUC131LD2AE as the microcontroller. It operates at 50MHz clock speed, has 64KB Flash memory (twice of Arduino Nano) and 8KB SRAM (four times of Arduino Nano). CT-ARM is in charge to control and communicate the sensor nodes through wireless communication with nRF24L01 module. It is interfaced through the SPI communication. As mentioned previously, all the data acquired is sent to the Host PC through UART communication.
Next, the sensor node block diagram is presented here. The microcontroller used was the Arduino Nano which uses Atmega328P chip. There are three disaster monitoring at the sensor node, they are the bridge health monitoring, earthquake monitoring and sea level monitoring. Besides, there is also a simulated actuator, which is made up of a micro servo motor. Similar to the central hub, nRF24L01 module is used for the wireless communication.